Financial exchanges such as the New York Stock Exchange, the American Stock Exchange, the NASDAQ, and others provide traders and brokers with facilities for publicly buying and selling securities and other financial instruments. Raw quotes and trade information from these exchanges may be collected, processed, and distributed to vendors such as Bloomberg, Thomson Reuters, and others. These vendors then provide processed quote and trade information to the general public, including the brokers and traders.
Alternative Trading Systems (ATS) are non-exchange venues that match buyers and sellers, often anonymously. These alternate systems provide access to non-public liquidity sometimes termed dark pools of liquidity. A crossing network is an example of an ATS that matches buy and sell orders electronically. A crossing network may receive raw quotes and trade information in the form of a direct data feed from an exchange. This data is then used to determine a price at which various securities are bought and sold within the crossing network. Crossing networks may allow large orders to be posted, without revealing the price or the identity of the buyer or seller, thus reducing the impact of the trade on the overall market. Dark pool transactions are recorded on the national consolidated tape as over-the-counter (OTC) transactions.